There are many prior art devices for sealing a closure member and an opening or hatchway in a housing. A vast majority of such prior part devices provide only a single seal and not a redundant or double seal as does the present invention. None of the known prior art devices are suitable for long term use on spacecraft or aircraft to seal low pressure atmosphere against vacuum. Most known prior art devices used with spacecraft or aircraft include elastomeric O-rings and other purely elastomeric seals, metal seals, elastomeric seals molded into metal gasket plates, or internally sprung elastomeric or plastic seals.
There are also various patents which relate to devices for providing a seal between adjacent surfaces of a closure member and a compartment. These patents generally teach the use of a single seal only which is not normally intended for use in spacecraft or aircraft. U.S. Pat. No. 2,686,343 discloses a sealing device for a pressurized aircraft including an elongated elastomeric tube. U.S. Pat. No. 3,308,727 discloses a sealing device for use between a manhole and a manhole cover comprising a cushioning ring having an outer ring member and an inner ring member having diverging arms. U.S. Pat. No. 3,763,595 discloses an elastomeric seal for providing a fluid-tight seal between a closure member and a structure extending around the opening of a hatchway. U.S. Pat. No. 3,777,424 discloses a weather seal for a railway car door, which seal is formed of an elastomeric material. U.S. Pat. Nos. 1,906,110, 2,827,280, 3,284,957, 4,474,344, and 4,535,565 are illustrative of other prior art devices for sealing between compartments or between a compartment and the outside thereof.
The prior art sealing devices, particularly when used on spacecraft or aircraft, have numerous disadvantages or drawbacks. For example, those sealing devices which rely upon an elastomer to maintain the sealing contact force are subject to failure over a period of time due to the compression set of the elastomer and it is extremely difficult to replace the elastomer only. Metal seals normally require large clamping forces to seal, thus necessitating stiff, heavy, flanges which are not adaptable for lightweight spacecraft or aircraft. Currently available metal seals and internally sprung elastomeric or plastic seals are extremely, rigid and of one piece, and, if used on a circular opening or hatchway, cannot fit through the opening or hatchway to be sealed. Most prior art sealing devices also require a relatively large space for storage of spares and are difficult to mount. Many of the prior art sealing devices also require special machining since they are mounted in a recess or groove. Many prior art sealing devices are not constructed such as to permit the replacement of the elastomeric material only, but require the replacement of the entire sealing device.
The present invention overcomes the numerous disadvantages, drawbacks or deficiencies of the prior art devices in that it provides a redundant (two sealing points) elastomeric seal energized by metal springs while allowing the easy replacement of the elastomers independently of the metal springs. The metal springs maintain the stress in the elastomers over a very long period of time, well beyond the time a pure elastomeric seal would have failed due to compression set. The surfaces which the seal of the present invention interfaces with can be smooth, with no special machining being required except for simple tapped retention holes; thus lowering costs and simplifying the elastomer replacement process.
Accordingly, it is an object of the present invention to provide a new and improved device for sealing the opening or hatchway between two compartments or one compartment and the outside.
It is a further object of the present invention to provide a double face device for mounting between two surfaces to provide an airtight and fluid-tight seal between the surfaces.
It is still a further object of the present invention to provide an easily replaceable, long lasting, ultra low leakage seal for use in a spacecraft or aircraft to contain the atmosphere therein.
It is yet a further object of the present invention to provide a long lasting, redundant (two sealing points), elastomeric seal energized by metal springs which maintain the stress in the elastomeric seal over a very long period of time, well beyond the time a pure elastomeric seal would have failed due to compression set.